U.S. patent number 6,853,203 [Application Number 10/373,654] was granted by the patent office on 2005-02-08 for oil quality measurement device.
This patent grant is currently assigned to Mann & Hummel GmbH. Invention is credited to Markus Beylich, Andreas Franz.
United States Patent |
6,853,203 |
Beylich , et al. |
February 8, 2005 |
Oil quality measurement device
Abstract
An oil quality measurement device for an oil circuit (1), which
includes an oil condition sensor (2) and an analysis circuit (3).
The oil condition sensor (2) is constructed as a capacitive or
impedance spectroscopic sensor (4) and attached to the filter
element (14) in such a way that, when the filter element (14) is
replaced, the oil condition sensor (2) is also automatically
replaced.
Inventors: |
Beylich; Markus (Ludwigsburg,
DE), Franz; Andreas (Kornwestheim, DE) |
Assignee: |
Mann & Hummel GmbH
(Ludwigsburg, DE)
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Family
ID: |
27675092 |
Appl.
No.: |
10/373,654 |
Filed: |
February 26, 2003 |
Foreign Application Priority Data
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Feb 27, 2002 [DE] |
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102 08 600 |
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Current U.S.
Class: |
324/698; 324/658;
324/691 |
Current CPC
Class: |
B01D
29/60 (20130101); B01D 35/143 (20130101); G01N
33/2888 (20130101); G01N 27/226 (20130101); G01N
27/02 (20130101) |
Current International
Class: |
G01N
33/28 (20060101); G01N 33/26 (20060101); G01N
27/02 (20060101); G01N 27/22 (20060101); G01R
027/08 () |
Field of
Search: |
;73/53.05,61.75 ;123/573
;324/658,663,698,61.41,691 ;356/70 ;210/168 ;340/591 ;702/50 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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19708067 |
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Sep 1998 |
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DE |
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1091098 |
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Apr 2001 |
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DE |
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10000148 |
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Jul 2001 |
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DE |
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10025690 |
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Nov 2001 |
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DE |
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2306660 |
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May 1997 |
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GB |
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99/58965 |
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Nov 1999 |
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WO |
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Other References
Search Report EP 02 10 2817, Jun. 2003..
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Primary Examiner: Le; N.
Assistant Examiner: Benson; Walter
Attorney, Agent or Firm: Crowell & Moring LLP
Claims
What is claimed is:
1. An oil quality measurement device for an oil circuit, comprising
an oil condition sensor electrically connected to an analysis
circuit, wherein the oil condition sensor is constructed as a
capacitive or impedance spectroscopic sensor and is attached to a
filter element such that the oil condition sensor is also replaced
when the filter element is replaced, wherein the analysis circuit
is disposed on a filter receptacle for an oil filter which
comprises said filter element, and wherein the filter element is
enclosed by a filter housing which is screwed into the filter
receptacle, and annular contacts are provided on the filter element
for establishing electrical contact between the oil condition
sensor and the analysis circuit.
2. An oil quality measurement device for an oil circuit, comprising
an oil condition sensor electrically connected to an analysis
circuit, wherein the oil condition sensor is constructed as a
capacitive or impedance spectroscopic sensor and is attached to a
filter element such that the oil condition sensor is also replaced
when the filter element is replaced, wherein the oil condition
sensor is arranged on a filtered oil side of the filter
element.
3. An oil quality measurement device for an oil circuit, comprising
an oil condition sensor electrically connected to an analysis
circuit, wherein the oil condition sensor is constructed as a
capacitive or impedance spectroscopic sensor and is attached to a
filter element such that the oil condition sensor is also replaced
when the filter element is replaced, wherein the oil condition
sensor is integrated into an end plate of an oil filter which
comprises the filter element, wherein the end plate contacts an end
of the filter element.
4. An oil quality measurement device for an oil circuit, comprising
an oil condition sensor electrically connected to an analysis
circuit, wherein the oil condition sensor is constructed as a
capacitive or impedance spectroscopic sensor and is attached to a
filter element such that the oil condition sensor is also replaced
when the filter element is replaced, wherein the filter element
annularly surrounds a substantially cylindrical foraminous support
body, and the oil condition sensor is constructed as a hollow body
and is arranged between the filter element and the support
body.
5. An oil quality measurement device for an oil circuit, comprising
an oil condition sensor electrically connected to an analysis
circuit, wherein the oil condition sensor is constructed as a
capacitive or impedance spectroscopic sensor and is attached to a
filter element such that the oil condition sensor is also replaced
when the filter element is replaced, wherein the filter element
annularly surrounds a substantially cylindrical support body, and
said support body is constructed as the oil condition sensor.
Description
BACKGROUND OF THE INVENTION
The present invention relates to an oil quality measurement device
for an oil circuit.
The reliable operation of an oil circuit for lubricating an
internal combustion engine in a motor vehicle or a hydraulic
installation, for example, requires good oil quality. In the course
of operation of an oil circuit, the oil quality may deteriorate,
for example, due to dirt contamination, decomposition, water
absorption, or the like. In lubricant oil circuits of internal
combustion engines, soot particles, abraded metal, and even fuel,
among other things, enter the oil in an undesired way and reduce
its lubricating ability.
To maintain a specific oil quality over a predetermined cycle, an
oil filter, which serves to filter contaminants which arise out of
the oil, is arranged in the oil circuit. Particularly during the
operation of diesel motors, corrosive acids may arise in the oil,
for whose neutralization appropriate metallic materials are
positioned in the oil filter. Unfavorable operating parameters,
such as frequently performing a cold start, may lead to premature
deterioration of the oil quality, even within the predetermined oil
change interval. As a consequence, increased wear or even damage to
the hydraulic installation and/or drive motor may occur.
To avoid these problems, U.S. Pat. No. 4,791,374 discloses an oil
circuit in which an oil condition sensor is provided for measuring
the oil quality. If the measured parameters deviate from a target
range, deterioration of the oil quality may be recognized early and
an oil change can be initiated. High requirements are set on the
quality and particularly the service life of the oil condition
sensor, which, among other things, makes the measurement device
expensive and uneconomical.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved oil
quality measuring device for an oil circuit.
Another object of the invention is to provide an oil quality
measuring device for an oil circuit which is highly reliable.
A further object of the invention is to provide an oil quality
measuring device which is economical and cost-effective.
These and other objects are achieved in accordance with the present
invention by providing an oil quality measurement device for an oil
circuit, comprising an oil condition sensor electrically connected
to an analysis circuit, wherein the oil condition sensor is
constructed as a capacitive or impedance spectroscopic sensor and
is attached to a filter element such that the oil condition sensor
is also replaced when the filter element is replaced.
For this purpose, an oil quality measurement device for an oil
circuit, having an oil condition sensor and an analysis circuit, is
proposed. The oil condition sensor is constructed as a capacitive
or impedance spectroscopic sensor. This sensor is arranged in an
oil filter of the oil circuit and is automatically replaceable as a
unit together with the filter element. The analysis circuit is
fixedly mounted on a housing of a component of the oil circuit,
separate from the oil filter. By providing such a sensor together
with an analysis circuit, it is possible to reliably measure a
variety of parameters for detecting the oil quality.
The sensor may be constructed simply and cost-effectively in this
case without impairing its reliability. Regular replacement of the
sensor together with the filter element ensures the reliability of
the measurement device as a whole over a long service life. The
analysis circuit, which is fixedly arranged on the oil circuit
outside the oil filter, is protected from the influence of the oil
and may be designed at low cost for a long service life extending
over multiple oil change intervals or even throughout the overall
service life of the system.
Especially if the oil condition sensor and the analysis circuit are
designed for measurement by impedance spectroscopy, high system
reliability can be achieved at low cost. In impedance spectroscopy,
the dielectric constants, the loss angle, and the conductivity of
the oil are determined as a function of a measurement voltage
frequency applied to the capacitive sensor.
From the viewpoint of measurement technology, the oil to be
measured, which has multiple components, some of which are harmful,
constitutes a complex resistor. A real part and an imaginary part
of its impedance spectrum may be determined as a function of the
measurement frequency in the manner described above. Each
contaminant component in the oil has its own specific individual
conductivity, which may be identified in the measured impedance
spectrum. Thus, the oil to be tested may be checked in regard to
the content of multiple contaminants using a single measurement
device, and particularly using one single, simply constructed
capacitive sensor in the oil filter.
The parts lubricated and/or moved in the oil circuit are reliably
protected by monitoring the oil quality. Through monitoring of the
oil contents, protection for the filter element is also provided,
since an acid component in the oil, which reduces the useful life
of the filter element, may be detected in a timely manner.
Integration of the sensor into the oil filter such that the filter
and sensor are replaceable together helps to protect the sensor
element itself from extended exposure to corrosive acids in the
oil, for example, in diesel motors.
In one advantageous embodiment, a filter housing may be screwed
into a filter receptacle. Electrical contact between the oil
condition sensor and the analysis circuit is achieved via annular
ring contacts. A reliable, planar contact is provided independently
of the angular position of the filter element. Alternatively or in
combination with this, a connecting plug may be provided, which is
preferably arranged outside the oil filter housing and is therefore
protected from corrosive influences.
By arranging the analysis circuit directly on the filter receptacle
of the oil filter, short electric paths between the sensor and the
analysis circuit are provided, which contributes to increasing the
measurement precision. In such a case, the analysis circuit may
advantageously be positioned in a separate housing, which is
attached to the filter receptacle. In this way, the analysis
circuit may be easily replaced in case of damage.
Modular oil filters of otherwise identical construction may be
alternately made and supplied with and without an oil quality
measurement device. It is also possible to retrofit an existing oil
circuit with an oil condition sensor and an analysis circuit.
It has been found advantageous to position the oil condition sensor
on the filtered oil side of the oil filter in order to increase the
measurement precision. The concentration of foreign materials in
the oil is comparatively low at this location and relatively free
of suspended particles. These factors favor the acquisition of a
precise and accurate measurement result.
In one advantageous embodiment, the oil condition sensor is
integrated into an end plate of the filter element. The end plate
is contacted by a good flow of the oil to be checked and thus the
end plate offers a suitable location for precise measurement. When
manufactured as a separate single part, it avoids the need for
structural changes to the remaining components of the oil
filter.
To increase the precision of the measured result, it has been found
advantageous to construct the sensor with the greatest possible
geometric extent or measurement length. For this purpose, it is
advantageous to use a spiral-shaped or meandering arrangement, for
example, of an electrically conductive measurement wire, metal
strip, or the like, as a result of which a large overall
measurement length may be housed in a small installation space.
In an advantageous embodiment in which the oil filter includes a
substantially cylindrical supporting body and a filter element
which encloses the supporting body, the oil condition sensor may be
constructed as a cylindrical hollow body and may be arranged
between the support body and the filter element. Due to the
resulting support of the condition sensor on all sides, the
mechanical stress on the condition sensor remains low. At the same
time, there is a good flow of oil around the sensor, which
contributes to increasing the measurement precision.
In an advantageous refinement of this embodiment, the support body
of the oil filter is itself constructed as the oil condition
sensor. This contributes to reducing the number of parts and the
complexity of the system.
Particularly in oil filters in which only the filter element is
replaced as an individual part, it may be advantageous to attach
the oil condition sensor permanently to the filter element. This
assures that the sensor will also be replaced when the filter is
changed and prevents undesired extended operation of the sensor
beyond its constructively predetermined service life.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described in further detail hereinafter with
reference to illustrative preferred embodiments shown in the
accompanying drawing figures, in which:
FIG. 1 is a partially sectioned view of an oil filter for a
symbolically illustrated oil circuit having a foraminous support
constructed as an oil condition sensor;
FIG. 2 is a partially sectioned view of a variant of the
arrangement shown in FIG. 1 having an oil condition sensor
constructed as a cylindrical hollow body arranged between the
support body and the filter element;
FIG. 3 is a partially sectioned view of a further oil filter
arrangement having a wire-like oil condition sensor permanently
attached to the filter element;
FIG. 4 is a diagrammatical illustration of details of a helically
wound wire forming an oil condition sensor;
FIG. 5 is a schematic illustration of a meandering oil condition
sensor attached to an end plate of the filter element;
FIG. 6 is a schematic illustration of an alternate oil condition
sensor configuration also attached to an end plate of the filter
element.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1 shows a sectional illustration of an oil filter 5 of a
schematically outlined oil circuit 1, using the example of a
lubricant oil circuit for a truck diesel motor. Comparable
arrangements may also be provided for lubricant oil circuits in
passenger vehicles, for gear oil circuits, and for hydraulic oil
circuits.
In the oil circuit 1, an oil filter 5 is provided, which, in the
illustrative embodiment shown, comprises a filter housing 16
screwed into a filter receptacle 6. A cylindrical, perforate or
foraminous support body 12 and a filter element 14, which is also
cylindrical and which encloses the support body 12, are positioned
in the filter housing 16. The support body 12 and the filter
element 14 are held in the axial direction between an end wall of
the filter housing 16 and the filter receptacle 6. The filter
housing 16 may be screwed into the filter receptacle 6 using a
thread 17 and is sealed in relation to the filter receptacle 6 via
a circumferential O-ring 18.
The flow direction of the oil in the oil circuit 1 is indicated by
the arrow 21, according to which the oil is conducted through an
inlet 20 to an inflow side 13 of the oil filter 5. In the oil
filter 5, the oil flows radially through the filter element 14 from
the outside to the inside. The cylindrical filter element 14 is
enabled to withstand the resulting pressure differential, which
acts in a radially inward direction, as a result of the supporting
effect of support body 12. The filtered oil side 10 of the oil
filter 5 is radially inside the filter element 14. In order to
discharge the filtered oil, the inside of the filter element is in
fluid communication with an outlet 19 in the filter receptacle
6.
In the illustrative embodiment shown in FIG. 1, the support body 12
is constructed as an oil condition sensor 2 in the form of a
capacitive sensor 4 and is therefore on the filtered oil side 10 of
the oil filter 5. In order to provide electrical contact between
the sensors 2 and 4 and an analysis circuit 3, an annular ring
contact 7 is provided in the vicinity of each of the end faces of
the supporting body 12. Analysis circuit 3 is described in greater
detail in connection with FIG. 3.
FIG. 2 shows a variant of the arrangement shown in FIG. 1, in which
the capacitive sensor 4 is constructed as a cylindrical hollow body
15 and is positioned between the support body 12 and the filter
element 14. The remaining features and reference numbers of the
arrangement shown in FIG. 2 correspond to those shown in FIG.
1.
The capacitive sensor 4 shown in FIGS. 1 and 2 may be constructed
from stamped or etched sheet metal, from wound or braided or
otherwise shaped wire, as an etched circuit board, or the like. In
this case, the sensor 4 is made of an electrically conductive
material, which advantageously has a high corrosion resistance.
Stainless steel, titanium and carbon fibers have been shown to be
suitable sensor materials.
FIG. 3 shows a further arrangement of a filter 5 comprising a
cylindrical support body 12 and a likewise cylindrical filter
element 14, which are held in a filter housing 16 and a filter
receptacle 6. An end plate 11 is provided at each axial end of the
filter element 14. The oil condition sensor 2 is constructed as a
capacitive sensor 4 and is permanently attached to the radially
outer side of the replaceable filter body 14.
An analysis circuit 3 is arranged in a separate housing 9 on the
outside of the filter receptacle 6 and fixedly mounted on the
filter receptacle 6. A combination of annular contacts 7, a line 22
which extends through the filter receptacle 6 from the outside to
the inside, and a connector plug 8 is provided to establish
electrical contact between the sensors 2 and 4 and the analysis
circuit 3. The analysis circuit 3 in the separate housing 9 may be
replaced as needed by releasing the plug connector 8.
It may also be advantageous to have an arrangement in which the
analysis circuit 3 is integrated into the filter receptacle 6. In
the illustrative embodiment shown in FIGS. 1 to 3, the oil filter 5
and/or the sensors 2, 4 are intended to be replaced together with
the filter element 14. It may also be advantageous to replace the
sensors together with a module comprised of the filter element 14
and the filter housing 16.
FIG. 4 shows a schematic perspective illustration of a detail from
the filter element 14 shown in FIG. 3. In this case, the oil
condition sensor 2 is constructed as a helically wound stainless
steel wire 25, and wrapped around the radially outer side of the
filter element 14. It may be advantageous to interweave, adhesively
bond, rivet, or otherwise fixedly attach the oil condition sensor 2
to the radial outside of the filter body 14. Likewise, it may be
advantageous to attach the oil condition sensor 2 to the radial
inside of the filter body 14.
FIG. 5 shows a schematic illustration of a construction of the end
plate 11 shown in FIG. 3, in which the oil condition sensor 2 is
integrated into the end plate 11. The oil condition sensor 2, which
is constructed as a capacitive sensor 4, extends as a meandering
conductor track 26 on the surface of the end plate 11 and is
provided with two radially outwardly extending connector contacts
23 and 24.
In the variant of the arrangement shown in FIG. 5 which is shown in
FIG. 6, the conductor track 26 for forming the sensors 2, 4 has a
spiral-shaped course on the surface of the end plate 11. Respective
radially inner and outer contacts 23 and 24 are provided to
establish electrical connections to each of the sensors 2, 4.
The foregoing description and examples have been set forth merely
to illustrate the invention and are not intended to be limiting.
Since modifications of the described embodiments incorporating the
spirit and substance of the invention may occur to persons skilled
in the art, the invention should be construed broadly to include
all variations within the scope of the appended claims and
equivalents thereof.
* * * * *